Question

I am trying to understand how to create array lists in Java, for some reason I am getting an error saying to change the type of myList to ArrayList even though I saw this example from a different post on stack overflow and it seemed to work.

What I am trying to do is simply create a List, add three strings to it and iterate through it and print it out.

On a side note, is it possible to add integers, strings, and objects all to the same list?

I’d appreciate any guidance in this regard.

    List myList = new ArrayList(); 


            myList.add("hello");
            myList.add("World");
            myList.add("!");

//print contents
System.out.println(myList);

Answer 1

My guess is that you’ve imported java.util.ArrayList, but not java.util.List. The code you’ve posted works if you import both:

import java.util.ArrayList;
import java.util.List;

class Test
{
    public static void main(String args[])
    {
        List myList = new ArrayList(); 

        myList.add("hello");
        myList.add("World");
        myList.add("!");

        //print contents
        System.out.println(myList);
    }
}

Having said that, I’d strongly urge you to use generics:

List<String> myList = new ArrayList<String>();